The present invention relates to an underfloor heating system for heating the floor of a room and its heating method. The underfloor heating system is very simple in construction and very low in construction cost. The underfloor heating system can be constructed in a short period of time. Further, it prevents air pollution and it maximizes heating effect as a heating means to be used not only for traditional Korean type or built rooms but also for all types of structures, such as office buildings, exhibition halls and public assembly rooms. In addition, and by use of night time generated electric power, much heat of a panel is regenerated heat, and then can be radiated heat on the panel during the daytime.
As to the traditional underfloor heating system of a room, stone slabs are installed on the upper part of flues in a hypocaust connected with a fuel hole and a chimney to be heated up directly by the burning fuel. Although physical human body treatment and heating effect are good by the radiation of infrared rays as those stone slabs are heated directly by the flames, it is still defective because thermal loss is great as a lot of thermal energy is drawn off from the fuel hole and chimney when a fire is not kindled and harmful gas is released into the air.
In the case of a hot water circulation-type underfloor heating system, there is required a lot of thermal energy for heating water as it uses water for distribution of heat. It is unable to produce the intended effect due to low heat distribution speed and local radiation. Moreover, as it collects the remaining heat entirely into its boiler, thermal efficiency is extremely bad due to a lot of thermal loss caused during the distribution of heated water. Nevertheless, installation expense and maintenance cost are excessive. As the radiation part of the concrete panel is small, heat is not stored. As relatively high-temperature thermal energy is radiated, thermal energy is quickly sent directly to the region underneath the ceiling. When the ceiling is high in temperature and the floor is cold, an undesirable heating effect for the human body is thereby produced.
Regarding the steam-type heating system, it releases intense heat from a limited part and hot air goes up toward the ceiling rapidly. In order to obtain the desired effect below 130 to 170 cm which is the height about that of a nose from the floor of a room, it requires an enormous amount of thermal energy. In such a case, an amount to be borne for purchasing holed briquets, oil or gas including transportation costs and a space to be occupied by such fuel are not inconsiderable. In case holed briquets are used, it involves a problem of disposing of briquet cinders and air pollution caused by harmful gas and briquet cinders presents such a serious problem that the dwelling environment is extremely unhygienic. In order to install such heating systems as described hereinabove, it not only requires a considerable amount of manpower but also wastes construction expenses, time and resources. It is impossible to install it in a high-rise building because the load thereof is so great. Its thermal efficiency is extremely low as compared with investment.
In order to solve such problems as described hereinabove, the present inventor filed a Korean application No. 85-923 for a patent. It aimed at producing heat isolation effect by removing a tamping layer and forming an airtight vacuum part between the floor and concrete panel. Although it is advantageous that the construction period can be substantially shortened by its simple process, materials be made minimal, it can be installed in a high-rise building by the minimization of load and the concrete panel itself can produce the uniform radiation effect, it is still defective because it requires the arrangement of water circulation pipes for the distribution of heat and it is consequently unable to obviate a defect caused by the use of water as a distributor of heat.
In order to eliminate such a defect as contained in the prior application, a so-called air heating system in which air is circulated as a heat distributor instead of water was devised. According to this device, an airtight vacuum cavity was formed between the floor and the concrete panel and air heated by a heat exchanger was forced to circulate in the said cavity to heat up the concrete panel. In this case, as the heated air circulates in the airtight circulation circuit, thermal loss was relatively small and the heating effect was thereby improved. At the same time, the device could obtain a uniform radiation effect and prevent the discharge of harmful gas. As the heat exchanger and circulation pump were operable by the use of home electricity, the problem involved in the purchase and storage of fuel and in the disposal of waste could be improved. However, as the heat exchanger, air circulation pipes and circulation pump had to be installed, installation expense was high, requiring a certain space. In particular, the loss of heated air caused by coming into contact with the open air while circulating through circulation pipes and heat exchanger, if kept warm, could not be eliminated completely.